Medical practice is faced with the task to produce artificial materials for replacement of soft tissues—muscular and subcutaneous tissue. They must be rather inexpensive, easy-to-make, and posses all specific physical and chemical characteristics including appropriate density and chemical inertness, the ability to shrink or swell, and the ability to be placed into the body which requires biological inertness, and, in particular, lack of antigenic activity causing rejection or any other tissue response. Additionally, the material must have a form which is suitable for injection into muscular tissue with minimum injury to the patient. Hydrogels based on polyarcylamide can be used for such purposes.